421  
ACUS01 KWNS 051946  
SWODY1  
SPC AC 051945  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0145 PM CST TUE DEC 05 2017  
 
VALID 052000Z - 061200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS  
AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL ALABAMA...  
   
..SUMMARY
 
 
THUNDERSTORMS COULD STILL IMPACT PARTS OF CENTRAL ALABAMA WITH SOME  
RISK FOR POTENTIALLY DAMAGING WIND GUSTS LATE THIS AFTERNOON AND  
EVENING.  
   
..20Z OUTLOOK UPDATE
 
 
THUNDERSTORM DEVELOPMENT IS NOW GENERALLY CONFINED TO THE PORTION OF  
THE SHARP SOUTHEASTWARD ADVANCING SURFACE FRONT PRECEDED BY  
SUBSTANTIAL SURFACE HEATING AND MODEST BOUNDARY LAYER  
DESTABILIZATION, FROM PORTIONS OF WEST CENTRAL ALABAMA INTO UPPER  
TEXAS/SOUTHWEST LOUISIANA COASTAL AREAS. HOWEVER, THE TENDENCY  
APPEARS TO BE FOR STORMS TO FORM ABOVE/TO THE IMMEDIATE COOL SIDE OF  
THE FRONT, OR TO BE QUICKLY UNDERCUT BY IT. THIS SEEMS LIKELY TO  
MINIMIZE ANY APPRECIABLE RISK FOR SEVERE WEATHER, PARTICULARLY GIVEN  
THE WEAK/WEAKENING NATURE OF THE LOWER/MID TROPOSPHERIC WIND FIELDS  
NEAR THE GULF COAST.  
 
ON THE NORTHERN PERIPHERY OF THE MORE APPRECIABLE PRE-FRONTAL  
BOUNDARY LAYER DESTABILIZATION (ROUGHLY SOUTH OF BIRMINGHAM AL  
THROUGH THE COLUMBUS/LA GRANGE GA AREAS), IT DOES APPEAR THAT  
LINGERING 850-700 MB FLOW ON THE ORDER OF 30-40+ KT COULD STILL  
ENHANCE CONVECTIVE DEVELOPMENT, AND CONTRIBUTE TO THE RISK FOR  
MAINLY LOCALIZED POTENTIAL DAMAGING WIND GUSTS. THIS MAY BE AIDED  
BY AN AREA OF INCREASING FORCING FOR LARGE-SCALE ASCENT, SUPPORTED  
BY LOW-LEVEL WARM ADVECTION.  
 
..KERR.. 12/05/2017  
   
PREV DISCUSSION
 
/ISSUED 1027 AM CST TUE DEC 05 2017/  
   
..MS/AL AREA TODAY
 
 
A DEEP SYNOPTIC CYCLONE WILL OCCLUDE TODAY OVER ONTARIO TO THE WEST  
OF JAMES BAY, WHILE AN ASSOCIATED SURFACE COLD FRONT MOVES EASTWARD  
ACROSS THE APPALACHIANS AND SOUTHWARD TOWARD THE GULF COAST.  
SEASONABLE MOISTURE RETURN IS ONGOING AHEAD OF THE FRONT WITH  
BOUNDARY-LAYER DEWPOINTS RANGING FROM THE LOW 70S ALONG THE  
NORTHWEST GULF COAST TO THE LOW-MID 60S AS FAR NORTH AS THE I-20  
CORRIDOR IN MS/AL. 12Z SOUNDINGS SHOWED RATHER POOR LAPSE RATES  
ALOFT, AND THERE WILL BE A GRADUAL TENDENCY FOR THE STRONGER  
LOW-LEVEL FLOW/SHEAR TO DEVELOP EASTWARD THROUGH THIS EVENING, ALONG  
THE NORTHEAST FRINGE OF THE SOMEWHAT MORE UNSTABLE WARM SECTOR.  
WILL MAINTAIN LOW WIND PROBABILITIES FROM THE PRIOR OUTLOOK FOR A  
FEW STRONG STORMS WITHIN THE BAND OF FRONTAL CONVECTION, BUT THE  
SEVERE-STORM THREAT IS ON THE LOWER MARGINS FOR AN OUTLOOK AREA.  
 

 
 
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